Back-spacing mechanism for type-writing machines.



J. A. SMITH. BACK SPAGING MECHANISM FOR T YPB WRITING MACHINES.

APPLICATION rum) MAY 21, 1910.

a snnnws-snnn'r 1.

Patented Feb. 11

INVENTOR,

WI TNESSES J. A. SMITH. BACK smcma MECHANISM FOR TYPE WRITING MACHINES. V

APPLIOATIOK FILED MAY 21, 1910.

Patented Feb. 11, 1913.

3 SHEETS-SHEET 2.

WITNESSES J. A. SMITH. BAGK SPACING MECHANISM FOR TYPE WRITING MACHINES.

APPLIOA T10N FILED MAY 21, 1910.

Patented Feb. 11, 1913.

3 SHEETS-SHEET 3.

. ED v STATES PATENT OFFICE.

JOHN/L. SMITH, OF HARRISBURG, PENNSYLVANIA, ASSIGNOR TO ELLIOTT-FISHER QOMPANY, OF HARRISBURG, PENNSYLVANIA, A. CORPORATION OF DELAWARE.

' Specification of Letters Patent.

Application filed May 21, 1910. Serial No. 582,725.

BACK-SPAGING MECHANISM FOR. TYPE-WRITING MACHINES.

To all whom it may concern:

relation of the carriage Be it known that 1, JOHN A. SMITH, a

citizen of the United States of America, re-

siding at Harrisburg, in the county 0t Dauphin and State of Pennsylvania, have invented certain new and useful Improvements in Back-Spacing lowing is a specification.

This invention relates to back spacingv mechanism which, while capable of use in with reference to the equipment of what is known as the Elliott-Fisher writing-adding machine.

The object of the invention is to produce an eflicient mechanism for back spacing the carriage, as for instance the distance of one letter space.

A subordinate object is to combine with the-back spacing mechanism proper, certain mechanisms. whereby the back spacing of the carriage will not be interfered with by the carriage dogging or decimal spacing mechanisms with which machines of the character herein illustrated are equipped- In the accompanying drawings-Figure 1 is a longitudinal sectional view of a portion of an 'Elliott-Fisher writing-adding machine equipped in accordance with my invention, the parts being disposed in the positions they normally occupy. Fig. 2 is a similar view showing the parts in the positions they assume at an intermediate point in the depression of the back spacing key. Fig. 3 is still another view of this character with the parts in the positions they assume upon the complete depression of the back spacing key. Fig. 4 is a rear elevation of the carriage of the machine designed more particularly to show the construction and mal spacing devices. Fig.5 is a detail sectional view of certain of the parts. Fig. 6 is a sectional view of a portion of the carriage showing the normal operation of the decimalspacingmechanism. Fig. 7 is a detail view showing the operation of the coacting trips of the decimal spacing mechanism during the back spacing movement of Mechanism for Type-WVriting Machines, ofwhich the foldogging and deci-.

' spring 11. This s iftin Patented Feb. 11', 1913.

the carriage. Fig. 8 is detail view of the decimal space trip arm and its associated parts. Fig. 9 is a transverse section through the carriage with certain of the parts broken away and others omitted, and'Fig. 10 is a similar view. p

Each part is indicated by its appropriate reference character wherever shown.

It is unnecessary for the purpose of the present disclosure to illustrate the entire Elliott-Fisher billing machine to the equipment of which the present invention is directed. Suflice it to say that the machine referred to andpartially illustrated in the drawings is what is known as a combined typewriting and adding machine, which includes a stationary flat platen and a ma chine frame mounted to travel thereover in the direction of line spacing. The platen is not shown, but the front and rear carriage supporting guides 1 and 2 of the main machine frame are indicated in Fig. 9. Upon the guides 1 and 2 of the main 'machine frame is mounted a carriage 3 which travels transversely of the-platen to letter space the writing and is under tension from carriage propelling mechanism which constantly tends to draw the carriage to the right. Upon the carriage 3 is mounted the print ing mechanism operated by keys 4, said keys and a portion of their connections being indicated in Fig. 9.

Through the center of the carriage is extended a feed spindle 5 geared to racks attached to the guides 2 and 3 in a manner well understood in the art and having fixed thereto an escapement wheel 6. Goacting with the escapement wheel are two escapement dogs 7 and 8 operated from a rock shaft 9 connected through suitable-instrumentalities with the keys 4. The dog 7 is and the do 8 is moved into engagement with said w eel against the resistance of a of the dogs takes place upon the depression of the key and .the dog 7 is withdrawn from the wheel 6 l with the next tooth of the escapement wheel 6, the carriage advancing the distance of one letter space during this'return of the:

- dogs to their normal positions. The parts a limited back spacing movement of the car-' thus far described are common to the Elliott-Fisher machine of commerce.

The back spacing mechanism which 1' have devised for the purpose of facilitating riage includes a back spacing lever 12 fulcrumed at 13 on the inner side of the back wall of the carriage 3 and carrying at its right hand end a back spacing pawl 14 pivoted at 15 and having its beak 16 urged toward the escapement wheel.6 by a spring 17 connected at one end to the "tail piece of f the pawl and at its opposite end to the lever 12. Extended along the left hand side or end of the carriage is the back spacing keylever 18 fulcrumed upon a post 19 and having at its front end a back spacing key.

20 located at the keyboard of'the carriage.

The rear end of the lever 18 is connected to the left hand end ver 12.

Normally, see Fig. 1, the pawl 14 .is held of the back spacing le- I mounted on the main machineframe and is away from the wheel 6 by a pin 21 fixed to the back wall of the carriage 3. Upon the depression of the back spacing key 20 the lever l8 is oscillated, thereby oscillating the back spacing lever 12, and causing the pawl 14 to descend with the left hand end of the y back spacing lever. That face of the pawl f 14 which is opposed to the pin 21 is so formed that as said pawl descends its beak is allowed to approach the wheel 6, engaging the same after more or less preliminary movement of the lever 12., Continued depression of the key will cause the pawl 14 which is now engaged with the wheel 6 to rotate the latter and thus cause the back spacing of the carriage, overthrow being prevented by the bottom wall 3 of the carriage 3 formed with a recess 3 for the reception of the lower end ofthe pawl as the latter reaches its limit of movement, see Fig. 3.

From what has been said it will be seen that the back spacing pawl 14 coacts at the opposite limits of its movement with fixed parts or members, to-wit the pin 21 and the bottom wall 3 of the carriage, such coaction serving to hold the pawl normally out of engagement with the wheel and in engagement withthe wheel at the limit of the back spacing stroke'to lock the escapement wheel 6 against overthrow. The back spacing mechanlsm is retracted and normally retained in the posltion shown in Fig. '1 by a retracting spring 22 secured at one end to the back wallof the carriage casing and at its opposite end to an arm 23 extended able',"'th'erefore, to provide means whereby the operation of the back spacing mecha nism' will automatically render the carriage;

dogging. mechanism inoperative and thus oppose no resistance to the back spacing operation.

' In the drawings I-have shown so much of the carriage dogging mechanism or retraction lock as is necessary to fully disclose the coaction between this mechanism and'the back spacing mechanism. In Fig. 1 for instance is shown a toothed plate or ratchet 24 fwhich is ordinarily formed at the under side of a register or computing device 25 a fragment of which is shown in the drawings and which it may be mentioned incidentally is therefore relatively fixed with respect to the moving carriage which supports operating connections, not shown, whereby the computing device is operated to add as the numeral :eys of the typewriter are operated to print numbers onthe work sheet. Coacting with the ratchet 24 is what is in effect a dogging lever 26 fulcrumed at 27 on the back wall. of the carriage. At the. right hand end'of the lever 26, looking fro-m the front of the machine, is a cam plate 28 which coacts with the teeth of the ratchet 24 in a manner to permit the forward movement of the carriage, but to prevent or'dog the retractile movement thereof. as long as the printing mechanism occupies a position opposite an adding field or column. The normal position of the dogging lever 01' member 26 is shown in Fig. 1.- y

To effectthe automatic release of the dogging mechanism when the back spacing mechanism is operated, the upper endof the arm of the back spacing lever 12' is pro vided with a pin 28 projecting through a slot 29 in the back wall of the casing and cotiperatively related to the tail piece 30 or adjacent end of the lever 26, the latter being preferably provided with a bevel'or cam 30 along which the pin 28 rides to swing the dogging lever 26 from its normal engaged position, shown in Fig. 1, to its ineffective or disengaged position, shown in Fig. 3. It will nowbe seen that when the back spacing key is depressed the backspacing pawl 14 will be urged toward the wheel 6, during which movement the pin 28 by coaction with the lever 26 will render the carriage dogging mechanism ineffective so that said dogging mechanism will oppose no obstruc tion to the back spacing .of the carriage when the pawl 14 finally engages the wheel, as shown in Fig. 2, and back spaces the latter. Y v

In the particular machine disclosed there is another mechanism which must be 'modified to prevent interference with the back spacing operation. This is what is known as the automatic. spacing mechanism for automatically spacing or skipping1 the machine over a decimal, comma or ot er s ace. The automatic spacing mechanism inc udes what is known as a retarding lever 31, one end of which coacts with a pin 32 project-' ing from the normally engaged dog 7. The opposite end of the lever 31 underlies an arm 33 extending from a rock shaft 34 having a bearing in the back Wall of the carriage casing and provided on its rear end with what is known as a trip arm 35 at the extremity of which is a pointed trip 36 de signed to coact with a pointed'trip 37 which is relatively fixed and is ordinarily carried by the register or computing device 25. The operation of this automatic spacing mechanism, which is well known in the art, is substantially as follows: When the last digit to the left of the desired space is printed upon the depression of the key, the pawls 7 and 8 of the escapement are shifted,v as heretofore explained, without material advance movement of the carriage. Upon. release of the key the dogs are r'e-shifted,

' the dog 8 being withdrawn from the wheel 6 and the normally en aged dog 7 moving back toward its engage position. Normally this re-shifting of the dogs is accompanied by a single letter space movement of the carriage, but we are supposing that this movement will bring the printing point of the carriage opposite the space desired, the

location of this space being determined of course by the adjustment of the normally fixed trip 37. Instead, therefore, of arresting the carriage after 'a single letter. space movement, the movement of the dog 7 toward its engaging position is retarded by the lever 31, this retardation being due to the fact that the normal letter space movement of the carriage brings the trip 36 of the trip arm 35 into engagement with the fixed trip 37 thus causing a momentary depression of the trip arm and the arm 33, which latter in turn coacts .with the retarding lever 31 to cause the latter to retard the return movement of the dog 7. This retardation or exaggeration of the normal operation of the esca-pement is only momentary, however,

and the consequence is that the dog 7 engages and arrests the wheel 6 after the carriage has advanced the distance of two letter spaces'instead of one, as normally.

As thus far described the automatic spacing mechanism is not new, but an under' standing of its operation is necessary to a comprehension of its relation to the back spacm --the printing point of the carriage is 0 pcsite the letter space immediately beyon or to the right of the space over which the carriage has been skipped, the operation of the back spacing mechanism will back space the carriage one step, thus presenting the printing point opposite the decimal or other space on the work sheet. This backward movement of the carriage will also present as j mechanism. It will be seen that if 5 the trips 36 and 37 in engagement, with the result that the dog 7 will be held out of the wheel '6 and the carriage will be permitted to again move forward as'soon as the back spacing key is'released. In other words, if, with the carriage located immediately to the right of the space which has been skipped, an attempt is made to back space the carriage, the latter will move back one space, but the automatic spacing mechanism will interfere with the holding of the carriage in its new position by the dog 7 and consequently the carriage will only remain in its back spaced position as long as the back s ace key is held depressed. It is impossib e, therefore, to back space across and 1 beyond the space previously skipped. To avoid this interferencewith the back spacing .operation by the automatic spacing means it is simply necessary to modify the spacing mechanism so that the latter will coact with the dog 7 on the forward movement only of the carriage. This end is at tained by forming the trip arm 35 in two parts 35 and 35", as shown in Figs. 4, 6, 7 and 8 pivotally connected, as by a screw pintle, 38 and yieldingly retained in a predetermined relative position by a spring 39. The trip 26 is formed on the member 35 which is also provided with a shoulder 40 abutting against the end of the member 35*.

. The relation of the parts is such that when the carriage is advancing in a forward direction, as shown in Fig. 6, the engagement of the trips 36 and 37 will effect no relative movement of the members 35 and 35, but will cause said members to move in unison from the rock shaft 34 as an axis thus efi'ecting automatic spacing in the manner heretofore explained. Upon the return movement of the carriage, however, the engage- I sult. Consequently, 1 now it is attempted For a more complete disclosure of the machine to which my invention is shown applied reference is made to Patents Nos. 829,971 to Laganke and Smith, and 922,559

to H. D. Bolton.

' It is thought that from the foregoing, the

construction and operation of the mecha nism constituting my invention will be clearly understood, but I reserve the right to use said invention in other than the speci- I escapement including an escapement wheel fled relation and to efiiect such variation of the illustrated structure as may come fairly within the scope of the protection prayed.

What I claim is 1. The combination with-a carriage, of controlling mechanism therefor including an escapement wheel and cooperating dogs, of back spacing mechanism including a back spacing lever and a pawl carried thereby and coacting with the escapement wheel, a spring tending to urge the pawl into engagement with the wheel, a fixed part normally holding the pawl out of engagement with said wheel, and another fixed part coacting with the pawl to prevent overthrow.

2. The combination with a carriage, of an escapement movable therewith and controlling the movement of said carriage, said and coacting dogs, and back spacing mechanism also movable with the carriage and including a back spacing lever, a pawl carried thereby in coiiperative relation with the escapement wheel, a spring tending to urge the pawl into engagement with the wheel, fixed parts coacting with the pawl to hold the;pawl normally out of engagement with the wheel and to positively hold the dog in engagement with the wheel at theend of the back spacing stroke, a back spacing key, and a suitable connection between the back spacing key and the back spacing lever.

3. The combination with a carriage and means for dogging the carriage against backward movement, ofback spacing mechanism operative to back space the carriage and cooperatively related to the carriage dogging means to control the latter.

4:. The combination with a carriage, escapement mechanism controlling the movement thereof in one direction, means for dogging the carriage against premature movement in the opposite direction, and

back spacing mechanism coacting with an element of the escapement and also coacting with the carriage dogging means'to render said dogging means ineffectlve.

5. The combination with a carriage, es-

capement mechanism controlling the movement thereof in one direction, means for dogging the carriage, key-operated back spacing mechanism for the carriage, and means whereby the operation of the back spacing key will render the carriage dogging means inefiective during the back-spacing movement of the carriage.

6. The combination with a carriage, of an escapement mechanism controlling the movement thereof in one direction, back spacing mechanism including a back spacing lever, a pawl carried thereby and coacting with an element of the escapement, and a back spacing key for operating the lever, carriage dogging mechanism including a ratchet and a dogging lever, and means movable with the back spacing lever and coacting with the dogging lever to move the same out of cooperative relation with the ratchet.

7 The combination with a carriage, of an escapement mechanism controlling the movement thereof in one direction, back spacing mechanism for the carriage, and automatic spacing mechanism operative during the movement of the carriage in one, direction but inefi'ective during the back spacing movement of the carriage,

8. The combination with a carriage, escapement mechanism controlling the ste by step advance thereof, back spacing mec anism for the carriage, automatic spacing mechanism including coacting parts brought into engagement by the-forward movement of the carriage to exaggerate the normal spacing thereof, one of said parts being arranged to yield ineffectively when said parts engage during the. back spacing movement of the carriage.

9. The combination with a carriage and an escapement mechanism controlling the normal step-by-step advance thereof, of back spacing mechanism for the said carriage,

carriage dogging mechanism, means for rendermgsald carnage dogging mechanism ineffectlve upon the operation of the back spacing mechanism, and automatic spacing .an escapement wheel and cooperating dogs,

a back-spacing pawl adapted toengage the escapement "wheel, a back-spacing lever the back-spacing stroke to prevent overcarrying said pawl, a spring urging the pawl throw of the wheel. 10 toward the escapement wheel, and two fixed In testimony whereof I affix my signature parts eoacting with opposite faces ofthe dog in presence of two witnesses.

at the opgosite limlts of its movement to i JOHN A. SMITH. hold the 0g normally out of engagement Witnesses: i with the wheel and to hold said dog firmly M. L: BOWMAN,

in engagement with the wheel at the end of W. M. BBEITINGER. 

